This is another in the SF Masterworks series and I’m not alone in thinking it’s brilliant:

Exciting, intelligent galaxy-spanning stuff that these days would require six brick-thick volumes. This is the real heady wine of science fiction – Terry Pratchett

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The story starts with two inventions – spindizzies (kind of anti-gravity engines) and anti-agathic drugs (that enable citizens to live for a thousand years) – and takes the reader on a journey to explore their exploitation. On the way, we encounter vast experimental stations on Jupiter, cities taking flight from earth to explore the galaxy, the economic collapse of the galaxy and even the end of time itself.